defmodule Veo do
  @moduledoc """
  A library for interacting with Supermaker AI's Veo video service.

  Provides utility functions for constructing URLs and performing
  common video-related operations.
  """

  @base_url "https://supermaker.ai/video/veo"

  @doc """
  Builds a URL to the Veo service with optional parameters.

  ## Examples

      iex> Veo.build_url()
      "https://supermaker.ai/video/veo"

      iex> Veo.build_url(query: [id: 123, format: "mp4"])
      "https://supermaker.ai/video/veo?id=123&format=mp4"

  """
  def build_url(opts \\ []) do
    query = Keyword.get(opts, :query, [])

    @base_url
    |> build_query_string(query)
  end

  defp build_query_string(base_url, []), do: base_url

  defp build_query_string(base_url, query) when is_list(query) do
    query_string =
      query
      |> Enum.map(fn {key, value} -> "#{key}=#{value}" end)
      |> Enum.join("&")

    "#{base_url}?#{query_string}"
  end

  @doc """
  Calculates the aspect ratio of a video given its width and height.

  ## Examples

      iex> Veo.aspect_ratio(1920, 1080)
      1.7777777777777777

      iex> Veo.aspect_ratio(1280, 720)
      1.7777777777777777
  """
  def aspect_ratio(width, height) when is_number(width) and is_number(height) do
    width / height
  end

  @doc """
  Converts seconds to a human-readable time format (HH:MM:SS).

  ## Examples

      iex> Veo.format_duration(65)
      "00:01:05"

      iex> Veo.format_duration(3661)
      "01:01:01"
  """
  def format_duration(seconds) when is_integer(seconds) do
    hours = div(seconds, 3600)
    minutes = div(rem(seconds, 3600), 60)
    remaining_seconds = rem(seconds, 60)

    pad = fn x -> Integer.to_string(x) |> String.pad_leading(2, "0") end

    "#{pad.(hours)}:#{pad.(minutes)}:#{pad.(remaining_seconds)}"
  end

  @doc """
  Determines if a given URL is a valid video URL (basic check).

  This function performs a simple check to see if the URL contains "video"
  and ends with a common video extension.  It does *not* validate the URL
  against a specific service.

  ## Examples

      iex> Veo.is_valid_video_url?("https://example.com/video/123.mp4")
      true

      iex> Veo.is_valid_video_url?("https://example.com/image.jpg")
      false
  """
  def is_valid_video_url?(url) when is_binary(url) do
    String.contains?(url, "video") && String.ends_with?(url, ~r/\.(mp4|avi|mov|webm)$/)
  end
end